Building in Docklands

Just come back from a short break in Greenwich/ Docklands area. Brilliant place to wander. Loved the emirates cable car. Much better experience than the London eye at a fraction of the price.Was struck by the sheer number of apartment skyscrapers being built in the area. Something that would cost 250,000 in my area of England was going for 1 to 2 million. Will they ever be filled. I am aghast that there are enough people in London earning high enough wages to afford to buy them. Anyone bought one? Or do investors buy them, wait till price goes up then sell them on to another investor who..........?Are you struggling to find anything to buy on 30 to 50 grand wages? Shouldn't they be building for lower earners?